Abstract

Eimeria species are important coccidian parasites causing significant economic losses from clinical and subclinical coccidiosis in poultry worldwide. The objective of this study was to identify the abundance of Eimeria species responsible for coccidial infections in commercial chicken flocks in Nigeria. Morphometric methods by oocyt sedimentation and microscopy were used to identify Eimeria species from pooled faecal samples randomly obtained from commercial chicken farms. While Real-Time quantitative Polymerase Chain Reaction (RT-qPCR) targeting the Sequence Characterized Amplified Region (SCAR) from the genomic DNA extracted from the faecal samples was used to determine the specific species of Eimeria. Morphometry identification resulted in three groups of oocyst category Eimeria based on the length were identified (BM group: E. brunetti and E. maxima; AM group: E. acervulina and E. mitis and NTP group: E. necatrix, E. tenella and E. praecox). The relative abundance of 3.0%, 52.0% and 45.0% were obtained for BM group, AM group and NTP group respectively. Molecular method detected Five Eimeria species were identified by real-time qPCR from the samples with species-specific relative abundance of 37.8%, 1.1%, 7.1%, 3.1% and 50.9% E. acervulina, E. maxima, E. necatrix, E. tenella and E. mitis; while E. praecox and E. brunetti were not detected. All markers utilized in these qPCR assays were absolutely species-specific and support reproducible quantification across a wide linear range, unaffected by the presence of non-target species or other contaminating DNA. The sensitivity of this assay indicated that DNA equivalent to a single sporulated oocyst can be consistently detected. Only five out of the conventional pathogenic species of Eimeria were detected in commercial chickens sampled in Nigeria. The epizootiological significance of the identified circulating Eimeria species is to enhance coccidiosis vaccination prophylaxis in Nigeria. 

Keywords

morphometry, molecular, coccidiosis, Eimeria, chicken